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(No Model.) 3 Sheets-Sheet 1.

S. D. FIELD.

' Sextuplex Telegraph. N0 242,411. Patented May'SI, 1881.

$111 (l2 cell s) N. PETERS. Phn oulho n hur. Wash'mgiun, D, Q

(No Model.) 3 Sheets-Sheet 2.

. S. D. FIELD.

SextuplexTelegraph. Patented May 31,1881.

(No Model.) 3 SheetsSheet 3.

S. D. FIELD. Sextuplex Telegraph. No. 242,411. Patented May 31, 1881.

ww gw/w UNITED STATES PATENT @EETCE.

STEPHEN D. FIELD, OF NEW YORK, N. Y.

SEXTUPLEX TELEGRAPH.

SPECIFICATION forming part of Letters Patent No. 242,411, dated May 31, 1881.

Application filed March 30, 1881. (No model.)

T 0 all whom it may concern:

Be it known that I, STEPHEN D. FIELD, a citizen of the United States, and a resident of the city, county, and State of New York, have invented certain new and useful Improvements in Multiple Telegra-phs, of which the following is a specification.

My invention consists, generally, in the combination, with a main line, of three independent receivdng-instruments, two of which are so constructed as to respond to changes in the strength of the current traversing the line, while the other receiving-instrument responds only to rhythmical pulsations in said current, and three keys or transmitters, two of which act to vary the strength of current upon the line without reference to its polarity, while the remaining one acts to produce rhythmical pulsa-tions in said current.

By applying to the hereinbefore-mentioned apparatus any one of the well-knownsystems of equatingor balancing six distinct communications, three in each direction,may be transmitted over the line at the same time. The apparatus is capable of being either as a triplex, quadruplex, or sextuplex telegraph, as maybe desired in any particular case.

In the accompanying drawings, Figure l is a diagram illustrating the principle of my invention and showing its application to the transmission of three simultaneous communications in the same direction from one terminal station to the other. Fig. 2 is a modification of the same. Fig. 3 shows the details of one of the receiving-instruments. Fig. 4 is a diagram representing one terminal station with three transmitters and three receivers arranged for sextuplex transmission in accordance with the principles of my invention.

Referring to Fig. 1, L represents the main telegraph-line, extending from station Ato station B, which may be supposed to be situated at a considerable distance from each other. At station A three independent transmitters are placed in connection with the line, as shown in the figure, where they are respectively designated as K, K and K. The keys K and K are each provided with circuit-preserving contact-springs, or other equivalent devices of well-known construction, whereby when the key is depressed a current may be transferred from one branch of a circuit to another without interrupting it. The contact-points which form the terminals of these branch cireui ts may conveniently be designated as resting and working contacts, respectively, meaning by the former the contact which the spring bears against when the key is at rest, and by the latter the contact which it bears against when it is depressed, as in the act of transmitting a signal. When the apparatus is at rest and neither of the three keys are depressed no current traverses the main line.

E, E and E are the transmitting-batteries, which are placed in branch circuits so connected with the several keys that the respective batteries may be thrown upon a line separate- 1 y or together without interrupting the circuit. It will be more convenient to consider the batteries E and E as two sections of one and the same battery, the section E being preferably so constructed and arranged that its total electro-motive force will be about twice as great as that of the section E. For the sake of illustration we may suppose the section E to consist of twelve cells. The absolutenumber of cells required will, of course, vary with the length of line through which the apparatus is to be operated or theresistance to be OVOICOI'IIG thereby; but the relative proportion between the electo-motive force of the two sections of batter I should be maintained.

Considering, in the first place, the operation of the keys K and K when they are employed for the simultaneous transmission of two independent sets of signals, as in quadruplex working, it will be observed that they may occupy four different positions, as follows: First, both keys up; second, key K down and key K up; third, K down and K up; and fourth, both keys down.

The circuit-connections between the keys K and K the batteries E and E the line L and the ground G, are such that four different electrical conditions may be produced upon the line, depending upon the positions of the keys. In the first position, which has already been referred to, and which is shown in the drawings, both keys are up, and no current whatever goes to the line which is connected directly with the earth at the sending-station. The circuit may be traced as follows: From the ground G, at the station A by wire 2, lever 3, (of the key K contact-spring 4, wires 5, 6, and 7, key-lever 8, and contact-sprin g 9, (of the key K wire 10, lever 11, and contact-spring 12, (of the key K,) and thence by wire 13 over the line L to station B. If, now, the key K be depressed, a new circuit is formed, which includes the battery-sections E and E in series, so that the electro-motive force of one is combined with or added to that of the other. The circuit now passes from the ground G, as before, to the wire 5, from wheneeit goes by the wire 14 to the positive pole of the battery-section E and from the negative poleof the section E by the wire 15 to the lever 16, (of the key K thence by contact-spring 17 and wire 18 to the positive pole of the battery section E, thence from the negative pole of the section E by the wire 19 to the contact-screw 20, and thence by spring 12 and wire 13 to the line, as before. Thus the depression of the key K transmits to line acurrent from eighteen cells of battery, which, for convenience of explanation, may be assumed to have an clectro-motive force of eighteen volts. It, now, the key K be depressed, the key K remaining up, the route of the current will again be changed, and may be traced as follows: From the ground G to the lever 16 of key K as in the last case, ineluding the batterysection E thence by wire 21, contact-point 22, contact-spring 9, wire 10, lever 11, (of key K spring 12, and wire 13 to the line. In this case the negative current from battery'section E only is sent to line with an electro-motive force equal to six volts. If both keys K and K be simultaneously depressed, the route of the current will be as follows: From the ground G to the wire 5, as in the last case; thence by the wire 6 to the contact-point 23, spring 17, and wire 18, to the positive pole of the battery-section E thence from the negative pole of the said battery by the wire 19 to contact-point 20, and thence by spring 12 and wire 13 to line. In this case a negative current from battery-section E having an electro motive force of twelve volts is sent to line.

The effect of these different strengths of current upon the apparatus at station B (the receiving-station) will next be considered. It and R are the electromagnets of two independent receiving-instruments, which are included in the main line in series, as shown in Fig. 1. Each of these electro-magnets has its core normally polarized to a certain degree of magnetic intensity and of like polarity by means of permanent magnets M and M placed in contact with their cores, or by other wellknown equivalent means for producing the same effect. The permanent magnetism thus induced in the magnets of the receiving-instrument It and R though of the same polarity, is of different intensity-that of R being considerably greater than that of R I have designated the magnetic intensity of the electro-magnet R as that of 15, and that of R as 9, by which it is to be understood that the intensity in R is equal to that which would he produced in a neutral core by the in fluence of a current transmitted from the other end of the line, having an electro-motive force equal to fifteen volts, and the intensity of the magnetism in the electro-magnet R is in like manner equal to that which would be produced by a current of nine volts.

Each of the receivirig-instruments It and R is provided with an armature, as shown at a (0 which armatures are provided with retracting-springs s 8 and are arranged to close a local circuit on the back contact-stop for actuating a sounder, register, or other equivalent instrument in a well-known manner. The normal tension of the springs s and s should be less than the normal attraction of the polarized cores of the electro-magnets R and R so that when no current is passing the armatures will both be held up to the magnets and the local circuits open. The helices of the electromagnets It and It are so wound, with refer ence to the normal polarity of the cores which they inelose, that the tendency of the currents received from station A will be to neutralize or reverse the normal magnetism.

In view ofthe foregoing explanation, the operation of the receiving-instrument may now be understood without diflicnlty. When the key K is depressed a current of eighteen volts is transmitted over the line, which is suflicient not only to overpower and destroy the normal magnetism of the electro'magnet It, but to produce a slight excess of magnetism therein ot' the opposite polarity; but this is not sulficient to hold the armature a against the tension of the spring 8, and it accordingly falls upon its back contact and produces a signal upon the localinstrument. The same current traversing the second electro-magnet R reverses it and produces a magnetic strength of9, which is precisely the same amount as it normall y possessed, but ot'opposite polarity. This reversal is efl'ected so quickly that the armature A does not have time to fall upon its back contact-stop and produce a signal. If,

now, the key K be alone depressed, a current of six volts is transmitted. This reduces the normal magnetic strength in the receiving-instrument R from 15 to 9, which, however, is still sufficient to resist the tension of the spring 8 upon the armature a, which, therefore, remains unatfected. In the same manner the normal magnetism of the receiving-instrument R is reduced from 9 to 3, which, in this case, is not sufficient to hold the armature.

Referring to Fig. 1, T is an eleetro-magnet, the armature of which is shown as consisting of a tuned steel bar, t, constituting what is technically termed a reed. This is rigidly secured at one end to a suitable support, while its other end is free to vibrate under the influence of the intermittent attraction of the electro-magnet T. The bar or reed t can vibrate only at a determinate rate, depending upon its construction. It is provided with a contact-spring, U, which is included, together with the electro-magnet T, in the circuit of a local battery, I. This arrangement constitutes an automatic self-interrupter, which is similar to the well-known device employed for ringing electric bells, except that the armature is limited to a certain rate of vibration, which cannot be altered without altering the construction of the instrument itself.

P is a pole-changing commutator of wellknown construction, which is continuously operated by an arm projecting from the reed t. The oflice of this pole-ch anger is to reverse the polarity of the main battery E with respect to the ground-wire 24 and the line-wire 25 at each vibration of the reed't without interrupting the circuit, it being understood that this apparatus is constantly in operation during the time in which the telegraphic apparatus is in use. The manner in which it acts upon the circuit of the main line will now be explained.

When the key K is depressed the route of the main circuit is changed and passes from the wire 1 to the wire 24, thence through the pole changer P and battery E and again through the pole-changer to the wire 25, thence to the spring 4, wire 5, and so on to the line I1, so long as the key K remains depressed. Therefore the battery Ff will be included in the main circuit, and its polarity will be reversed with great rapidity by the action of the reed 2, but without at any time interrupting the main circuit. These electrical vibrations, waves, or pulsations pass through the line and through the helices of all three of the receivin g-instru ments. They produce, however, but a comparatively small variation in the total strength of the current, while the pulsations succeed each other with such rapidity that the armatures of the receiving-instruments R and R are not perceptibly affected by them. The receiving-instrument R however, has for its armature a tuned bar or reed similar to the one at the transmitting-station, and so constructed that it has precisely the same fundamental or rate of vibration. This reed armature is therefore thrown into vibration whenever the key K is depressed, and continues to vibrate so long as the key remains depressed. The construction of this receiving-instrument, and the manner in which it operates a sounder or other like instrument, will be best understood by reference to Fi 3.

R is an electro-magnct mounted upon one pole, for example, the north pole of a permanent magnet, N. The vibrating armature or reed d is rigidly secured at one end to a standard, a, by means of a screw, 12, or otherwise, so that its free end is in close proximity to the pole or poles of the armature of the electromagnet It. The reed d is preferably of magnetized steel and of a normal polarity, which is opposite to that induced in the core of the magnet R by the permanent magnet N. A small electro-magnet, W, is mounted upon the reed cl and partakes of its vibrations. Upon a standard, (1 also mounted upon the reed d, is pivoted a soft-iron tongue or armature, d,

which is in close proximity to the electro-magnet 0. This armature d opens and closes the local circuit of a battery, 0, and a sounder or recording-instrument, S, through a contactpoint, (i The main circuit passes successively through the coils of the electro magnets R and r from L to G, as shown. The effect of this arrangement is that when the reed d is not in vibration the armature (1 rests upon the contact (P and keeps the local circuit of the sounder S closed. When, however, the reed is thrown into vibration a jarring or imperfect contact between the armature and its contactpoint is produced, which has the effect ofbreaking the local circuit. Consequently, whenever the transmitting-key K in Fig. 1 is depressed, the local circuit of the sounder S is broken by means of the pulsations which are transmitted .through the line; consequently the sounder responds to the movements of the said key. Under this arrangement, however, the signals will be reversedthat is, the local circuit of sounder S will be open when the transmittingkey K is depressed. This objection may be removed by means of any one of several wellknown expedients.

The connections of the key K may be reversed, so as to throw the vibrations on the line when it is raised and cut them ofi' when it is depreseed, or a local relay and additional local circuit may be provided in connection with the receiving-instrument, the manner in which these devices are arranged being well understood by those skilled in the art.

I in order to obtain the best results in practice. the ad action of the electro-magnet 1 should be very weak. The strength of this electromagnet maybe conveniently adjusted by means of a variable rheostat, I,-placed across its terminals so as to form a shunt, as seen in Fig. 3.

It is not absolutely necessary that the receiving-instrument B should be adjusted to a definite rate of vibration, as I have obtained good results by the use of an electro-maguet having an armature possessing the characteristics of a telephone-(1iaphragm, which, as is well known, responds with equal facility to rhythmical vibrations, whatever may be their pitch or rapidity of succession.

It is not at all essential that the communications which are transmitted by means of the key K shouldtraverse the line in the same direction as those which are sent from the keys K and K in Fig.2 I have shown an organization similar to that illustrated in Fig. 1, except that the positions of the key K and its corresponding rcceiving-instrument, R have been interchanged with reference to the positions of the other instruments, thus affording simultaneously two communications in one direction and one in the opposite direction.

In Fig. 4 [have shown myinvention applied to the system of circuits commonly termed the bridge duplex, whereby I am enabled to transmit three communications over a line in one direction and at the same time receive three from the distant station in the opposite l y M direction, thus constituting a sextuplex telegraph. The diagram shows the arrangement at one of the terminal stations. the other be ing precisely similar to it in every respect. I have omitted some of the details of the trans mitting and receiving instruments, as these are in every respect the same as those shown in Figs. 1 and 2, with the exception that the rcceiving-instruments 1t and It are provided with differential helices. The main line L passes through one ot' the differential helices of each instrument, and the artificial line L in the opposite direction through the other helix.

The third receivirig-instrument, R which responds to the rhythmical vibrations, is preferably placed in a bridge-wire between the main and the artificial lines, as shown in Fig. 4. Theprinciple of this arrangement and the practical application of it in its various modifications are well understood by those skilled in the art, and therefore will not require a more detailed description in this place.

I prefer, in most cases, to construct the receiving-instruments R and It with electromagnets instead of permanent magnets, as hereiubefore described, as their normal magnetic strength is more conveniently controlled and regulated when it is produced by a local battery. The particular description of receiv-. ing-instruments which I generally prefer to use in connection with the hereinbet'ore-de scribed system ot'telegraphy will form the subject-matter ofa separate application for Let ters Patent.

I claim as my invention- 1. The combination, substantially as hereinbefore set forth, of a main line, three inde' pendent receivirig-instruments, two of which respond to changes in the strength of the current upon the line and the other to rhythmical pulsations in said current, and three keys, two of which act to vary the strength of current and the other to produce rhythmical pulsations in said current.

2. The combination, substantially as hereinbefore set forth, of a key provided with one contact-spring playing between a resting and a working contact, a key provided with two independent contact-springs, each playing between a restiugand a working contact, a main battery in two sections, the tirst of which has greater electro-motive force than the second, a main line connected to the contact-spring of the first key, a branch which unites the resting-contact of the first key with the first contact-spring of the second key, a branch which unites the working-contact of the first key with the second contactspring of the second key and includes the greater section of the battery, an earth-circuit connected to the first resting-contact and to the second working-contact of the second key, and a branch extend ing from the earth-circuit to the first workingcontact and the second testing-contact of the second key, and including the lesser section of the main battery,whereby the current transmitted to line by the simultaneous depression of both keys will have an electro-motive force greater than that of the lesser battery and less than that of both batteries combined.

3. The combination, substantially as herein before set forth, of a main line, a main battery in two sections, one of which has a greater electroniotive force than the other, two independent keys, circuit-connections between said keys, battery, and line, whereby the strength of the current flowing to theline is controlled, an independent main battery, a pulsating reversing-rhootome controlling the current from said battery, and a third independent key, whereby the last-named battery and its rheotome may be thrown into or out of the mainline circuit.

4. The combination, substantially as hereinbefore set forth, ot'a main line and two independent receivirig-instruments included therein, having electro-magnets permanently polarized, of like polarity but of different magnetic intensity.

The combination, substantially as hereinbefore set forth, of a main line, two independent receiving instruments included therein having electromagnets permanently polarized, t' like polarity, but different magnetic intensity, and two keys,\vhereby the strength of current in the main line may bevaricd without changing its polarity.

6. The combination, substantially as hereinbet'ore set forth, of a main line, two independent receiving-instruments included therein h avin g perm a neatly-polarized electro-m agnets and armatures controlled by automatic springs, and a third independent receivlug-instrument having a polarized electro-maguet, and an armature responsive to rhythmical pulsations only.

7. The combination, substantially as hereinbcfore set forth, of an electromagnet in a main circuit, a reedarmature adjusted to a determinate rate of vibration, a su 'iplementary lever loosely hinged to a fixed support and normally resting in contact with the reed-armature, a supplementary electro-inagnet, also in the main circuit, for controlling the action of said supplementary lever, and a local receiving-instrument, the circuit of which is closed by the contact of the reed-armature and supplementary lever.

S. The combination, substantially as hereinbet'ore set forth, of a main line, an artificial line, two differential receiving-instruments, each having one of its opposing coils included in the main line and the otherin the artificial line, and a iioittlitterential receiving-instrument placed in a bridge-wire between the main and artificial line.

In testimony whereof I have hereunto subscribed my name this 25th day of March, A. D. 1881.

STEPHEN DU DLEY FIELD.

Witnesses:

MILLER G. EARL, OHAs. A. TERRY.

IlO 

